4 symptoms of clogged radiator in cars

Updated Mar 29, 2021 | Same topic: Handy Maintenance Tips

If your radiator is leaking, then it could be clogged.

What does a radiator do?

To simply put how an engine works, it burns fuel to produce power. In doing so, the engine gets hot due to the continuous combustion happening every second. Extreme heat will cause engines to be damaged which will eventually lessen the lifespan of your vehicle.

This is where the radiator takes its place in the complex operation of an engine. A radiator in a car is used to cool down the engine with the use of coolants through the process of dissipation. Without a working radiator, your car’s engine will overheat, damaging most of the engine parts such as the pistons and gaskets.

A car's radiator

A radiator is an essential component to keep the engine running

One of the most common problems every car owner experiences with their radiator is that it clogs after some time. There are scenarios where it is quite difficult to visually inspect if your car’s radiator is clogging since the problems take place inside. Usually, it is caused by build-ups of rusts or other sediments.

We would want our radiator to work in a good condition at all times to keep our engine cool and run for more years. As such, we have listed down four symptoms that can tell you if your car’s radiator is already clogged. We have also listed down things you can do if you encounter this type of problem.

A BMW with an intercooler

An intercooler is different from a radiator

4 Symptoms of a clogged radiator

Symptom #1: Leaking coolant

Coolants are constantly flowing around the engine and radiator with the help of the water pump. If your car’s radiator is clogged, then coolants will find another way which sometimes causes cracks in the radiator. The cracks or holes on the radiator are where coolants with constant pressure escape resulting in leaks.

If you see colored liquid out of your car, then it could be that the coolants are leaking due to a clogged radiator. You should start inspecting your radiator to determine the leak is indeed coming from it. Cracks or holes can happen anywhere in the radiator so might as well pull it out for thorough inspection.

Symptom #2: Overheating engine

With a clogged radiator, the coolants will not flow seamlessly around the engine cooling system which results in the engine overheating. Driving with an overheating engine is as terrible as it sounds since it can cause permanent damage to the parts which will cost you a hefty amount of cash for replacement or repair.

One of the easiest ways you can do to determine whether your engine is overheating is by checking the temperature gauge usually located on your car’s instrument gauge cluster. If the temperature gauge reading rises fast, then it means that your engine is experiencing an abnormal rise in temperature. An overheating engine can be caused by various reasons aside from a clogged radiator so make sure before buying a replacement.

Symptom #3: Coolant discoloration

There are various colors of coolants depending on the material used by a manufacturer. However, the most common color used in most engine cooling systems is green. Examining the color of your car’s coolant from time to time can help you determine whether it is time to replace it or not.

If your car’s radiator is clogged, then the color of your coolants can turn from green into a brown color similar to rust. The build-up of contaminants such as rusts has caused your coolants to discolor. With discolored coolants, it can also cause the fluids to increase their viscosity, making it more difficult for the coolants to flow around the system.

Symptom #4: Damaged radiator fins

Radiators are designed with fins that direct the airflow to cool down coolants. These fins can be damaged by driving through rough terrain at high speeds, excessive vibrations, debris such as gravel, and even from the high pressure of water hoses when cleaning.

If you see that your car is heating up faster than usual, then it could mean that your car’s radiator fins are damaged which disrupt the ideal airflow within the system. As such, check for any damage or bends to make sure that the radiator is the root of the problem. While you’re at it, remove any debris stuck in the fins that block the airflow as well.

A car with leaking coolants

Observe your car for coolant leak

>>> Related: 3 symptoms of a bad radiator cap & replacement cost

What should I do if my car radiator is clogged?

One of the things you can do if your car’s radiator is clogged is to super flush it. Super flushing your engine cooling system can take a long time to do. What a super flash does is it cleans your car’s engine cooling system from all the contaminants it had accumulated including rusts.

To do this, you need a chemical coolant flush, distilled water, and new coolants. Make sure that the engine is not running to avoid getting hurt from pressure in the system due to heat. The first step you should do to super flush your engine cooling system is to add chemical coolant flush to the system. This will help get rid of the build-ups within the system.

Flipping a radiator cap

Fill the prescribed coolants from your car's manufacturer for best cooling results

Go for a drive for a few days before moving on to the next step. After adding some miles to your car, drain the coolants. It should be dirty if the radiator is indeed clogged. Now, you should repeat the process again and again until the coolants are clear.

But you don’t need to wait for days before draining. You can go for a drive at least five minutes with max A/C settings to circulate the coolants. Use a chemical coolant flush and distilled water to drain out the clog. Once the coolants are clear, you can go ahead and fill in new coolants which should last for around 200,000 km. Be sure to fill the right balance between distilled water and coolants to avoid expansion especially in a cold climate.

However, if your radiator is damaged or you don’t want to super flush it, you can opt to buy a new one instead to assure good cooling results. A new radiator in the Philippines should cost you around Php 8,000. This estimate is excluding labor costs so just replace the clogged radiator yourself if you can do it.

Man holding a radiator in an engine bay

Without a radiator, your car's engine will overheat

FAQs about radiators in cars

Q: How long do car radiators last?

On average, a car radiator should last for around seven to nine years, depending on how well the part is maintained.

Q: What is the color of a coolant?

The most recommended color of coolants by most car manufacturers is green.

Q: How much is a radiator in the Philippines?

A new radiator should costs around Php 8,000, depending on the model.

Q: What causes car radiators to get clogged?

Rust is one of the most common reasons why radiators get clogged.

Q: What happens if my radiator gets clogged?

A clogged radiator will your engine to overheat since coolants are not flowing properly.

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Rex Sanchez

Rex Sanchez


Rex Sanchez grew up in Saudi Arabia where he saw and got into the automotive scene. He started his career for an aviation company in the said region, writing about turbines and rotors which are later distributed for educational purposes. And now, he joined Philkotse.com as a staff writer. Currently, he is the youngest on the team and is more than ready to grow in the field.

Facebook: https://www.facebook.com/rexsanchez09

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